Hydrofoil sailboat

ABSTRACT

A hydrofoil sailing craft including a main hull flanked by a pair of outrigger hulls extending forwardly of the main hull. The outrigger hulls mount depending hydrofoils which extend downwardly and towards each other and which may be adjustably positioned. The main hull mounts a rotatable mast which in turn serves as a support for a sail comprised of a leading, rigid airfoil and a trailing flexible sail portion. The stern of the main hull mounts a steering mechanism comprised of an inverted Vshaped hydrofoil which is pivotal relative to the main hull about both vertical and horizontal axes to control the direction in which the boat moves as well as lift.

United States Patent [191 Mankawich Apr.9, 1974 HYDROFOIL SAILBOAT [21] Appl. No.: 153,377

[52] [1.8. CI 114/39, 114/61, 114/66.5 H, 114/103 [51] Int. Cl B63b 35/72, B63h 9/06 [58] Field of Search 114/39, 66.5 H, 61, 102, 114/103 [56] References Cited UNITED STATES PATENTS 2,585,599 2/1952 Tchetchet 114/61 3,002,484 10/1961 Dube 114/61 3,026,121 3/1962 Ellam 114/102 X 3,342,155 9/1967 Hook 114/66.5 H

3,381,647 5/1968 Keeler 114/102 3,561,388 2/1971 Keiper 114/66.5 H

3,580,203 5/1971 Martin 114/39 3,008,442 ll/l961 Russell 114/39 2,351,542 6/1944 Paull 114/39 3,856,879 10/1958 Baker.- 114/39 UX 3,294,055 12/1966 McGuire 1l4/66.5 H

3,395,664 8/1968 Greenberg et al 114/39 FOREIGN PATENTS OR APPLICATIONS 88,973 7/1922 Germany 114/102 Primary Examiner-Duane A. Reger Assistant Examiner-Barry L. Kelmachter Attorney, Agent, or FirmHofgren, Wegner, Allen, Stellman & McCord [5 7] ABSTRACT A hydrofoil sailing craft including a main hull flanked by a pair of outrigger hulls extending forwardly of the main hull. The outrigger hulls mount depending hydrofoils which extend downwardly and towards each other and which may be adjustably positioned. The main hull mounts a rotatable mast which in turn serves as a support for a sail comprised of a leading, rigid airfoil and a trailing flexible sail portion. The stem of the main hull mounts a steering mechanism comprised of an inverted V-shaped hydrofoil which is pivotal relative to the main hull about both vertical and horizontal axes to control the direction in which the boat moves as well as lift.

10 Claims, 8 Drawing Figures PATENTED APR 9 I974 SHEET 3 BF 3 I-IYDROFOIL SAILBOAT BACKGROUND OF THE INVENTION For a goodly period of years, it has been recognized that conventional sailing craft are extremelyinefficient in converting the energy of wind into movement of the sailing vessel. Specifically, the two principal causes of inefficiency in the operation of sailing vessels reside in the drag of the hull within the water and inefficient conversion of wind energy by conventional, flexible sails.

As a result, there have been a number of proposals of sailing craft that eliminate one or the other or both of the principal causes of inefficiency through the use of hydrofoils to minimize drag and airfoils as sails for more efficient conversion of wind energy. Such attempts have proved their point as far as increasing the total efficiency of the operation of the sailing vessel but have not been greeted with widespread popularity for a variety of reasons. In particular, hydrofoil sailing craft, when operating at a sufficient speed so that the vessel hull is out of the water and the vessel is traveling only on hydrofoils, are extremely susceptible to capsizing unless provided with an extremely wide beam. However, if provided with a wide beam, the same are extremely difficult to transport over land.

Similarly, airfoil sails, being of a generally rigid nature, have oftentimes added sufficient weight to the craft as to offset their increased efficiency and/or cannot be readily dismantled when the sailing craft is to be stored or transported over land.

In addition, in order to steer such craft and/or control the lift of the hydrofoils, most proposals of hydrofoil sailcraft have involved rather complex linkages for use in steering and controlling lift and the resultant lack of simplicity has been a drawback to their extensive use by ordinary boating enthusiasts.

SUMMARY OF THE INVENTION It is the principal object of the invention to provide a new and improved sailing craft that may operate with increased efficiency over conventional craft through the use of hydrofoils and/or a sail comprised in part of an airfoil.

The exemplary embodiment of the invention trolled by rotating the hydrofoil about the horizontal axis.

The main hull rotatably mounts a mast which in turn mounts a sail. The forward portion of the sail is comprised of a relatively rigid airfoil while the trailing portion of the sail is comprised of a heavily battened, flexible, conventional sail. Means are provided regulating and locking the angle of the airfoil with respect to the main hull and in addition, means are provided for controlling the position of the flexible sail portion relative to the mast. In addition, a unique construction of elements comprising the airfoil permits its easy disassembly for transportation and/or storage purposes.

Other objects and advantages will become apparent from the following specification taken in conjunction with the accompanying drawings.

DESCRIPTION OF THE DRAWINGS FIG. I is a perspective view of a hydrofoil sailing craft made according to the invention;

FIG. 2 is an enlarged, fragmentary perspective with illustrating the steering mechanism and lift control device;

FIG. 6 is an enlarged, perspective view illustrating an outrigger hull and the appurtenances thereto;

FIG. 7 is a perspective view of a rudder runner attachment; and

achieves the foregoing object by means of a construction including a main hull flanked by two outrigger hulls, both of which extend forwardly of the main hull. Each outrigger hull mounts a hydrofoil which extends downwardly therefrom and towards the other outrigger hull. Means are provided for adjusting the angle of each hydrofoil relative to its respective outrigger hull.

The outrigger hulls are secured to the main hull by means of tubes which may be easily removed or, in the alternative, telescopingly collapsed. As a result, great stability in the craft is provided without sacrificing ease of transportation.

The main hull, for steering purposes and for controlling lift includes a unique'mechanism comprised of an inverted V-shaped hydrofoil which is mounted for rotation relative to the main hull atthe stern thereof about both a vertical and a horizontal axis. A single operator is provided for the V-shaped hydrofoil and when the same is rotated relative to the main hull about the vertical axis, steering is provided while lift may be con- FIG. 8 is a perspective view of an outrigger runner attachment.

DESCRIPTION OF THE PREFERRED EMBODIMENT An exemplary embodiment of a hydrofoil sailing craft made according to the invention is illustrated in FIG. 1 and is seen to comprise a main hull 10 flanked by a pair of outrigger hulls 12 and 14, respectively. The outrigger hulls l2 and 14 are secured to the main hull by means of parallel tubes 15 such that a substantial portion of each of the outrigger hulls l2 and 14 extends forwardly of the main hull 10.

Each of the tubes 15 is formed of two tubes 16 and 17 which may be releasably interconnected. According to one embodiment of the invention, the tubes 17 may telescope within the tubes 16 while according to another embodiment, an appropriate union employing an element (not shown) extending within a portion of both of the tubes 16 and 17 may be employed. The purpose of the foregoing construction is to permit easy disassembly for storage or transportation purposes. That is, by either telescoping the tubes 17 within the tubes 16 or by disconnecting the two, each of the outrigger hulls l2 and 14 may be brought into virtual abutment with the main hull 10 to result in a compact structure for storage or transportation.

In addition, diagonally arranged bracing supports in the form of two interconnected tubes 18 and 19 extend from the main hull 10 to respective ones of the outrigger hulls 12 and 14. Again, the employment of two separable tubes as the bracing supports permits easy disassembly for storage or transportation purposes. In this way, when it is desired to store or transport the sailing outrigger hulls 12 and 14 may be brought into virtual abutment with the main hull 10 to provide a compact structure for such purposes. The arrangement thereby permits construction of a craft having an extremely wide effective beam for stability purposes which may be extensively decreased for transportation or storage purposes.

The main hull includes a cockpit 20 for an operator of the craft as well as an upwardly extending mast 22. A sail, generally designated 24, is supported by the mast 22 and is comprised of a relatively rigid airfoil 26 located forwardly of the mast 22 and a flexible sail portion 28 rearwardly thereof.

As will be seen, the airfoil 26 is rotatable relative to the main hull l and a control structure, generally designated 30, is provided to position and lock the airfoil 26 at a desired position of rotation relative to the main hull 10. Also provided are sheet means, generally designated 32, for controlling the angular position of the flexible sail portion 28 relative to the airfoil 26.

The main hull also mounts a combined steering and lift control device, generally designated 34, having a handle 36 which may be manipulated by an operator in the cockpit 20 to control the direction in which the craft is traveling as well as lift characteristics of the craft. The steering and lift control mechanism 34 includes an inverted V-shaped hydrofoil 38 which is responsive to operation of the handle 36 in a manner to be described in greater detail hereinafter.

- Each of the outrigger hulls l2 and 14 mounts a hydrofoil 40 which extends downwardly from its respective outrigger hull and inwardly toward the other outrigger hull. Preferably, the hydrofoil elements 40 are located on their respective outrigger hulls as follows. The downward angle of the same with respect to a horizontal plane should generally be in the range of 30 to 60 and may be adjustable depending upon the load to be carried by the craft. The rake angle (that angle of the leading edge of the foil with a line transverse to the center line of the craft) should be in the range of to Finally, the angle of attack (that angle of a line drawn between the leading edge and trailing edge of each foil with respect to a horizontal plane) should be i the r ge. 9 519.15 h the fron ed e bqvethe trailing edge.

Turning now to FIG. 2, details of the mast 22, the sail 24 and the control devices 30 and 32 will be described. The mast 22 is seen to comprise a rod or pole journaled for rotation relative to the main hull by bearings 42. The mast 22 is received within a sheath 44 (FIGS. 2 and 3) which, at its lower end, includes a pair of rearwardly projecting, apertured lugs 46 pivotally mounting a boom 48 for the flexible sail portion 28.

As best seen in FIG. 3, the trailing edge of the sheath 44 also includes a keyhole slot 50 extending the length of the sheath 44 for receiving a bead on the forward edge of the flexible sail portion 28 to secure the same to the mast 22 in a conventional fashion. Also mounted near the lower end of the sheath 44 is a crank 52 for operating a small winch mechanism (not shown) within the sheath 44. The winch mechanism is operativcly associated with a halyard 54 within the sheath 44 which extends through the length thereof to a sheave 56 at the upper end which reverses its direction for connection to an eyelet 58 at the apex of the flexible sail portion 28. As a result, operation of the crank 52 may be employed to raise or lower the flexible sail portion 28.

The lower edge of the flexible sail portion 28 may be secured to the rearward end of the boom 48 by any suitable means. As illustrated, the flexible sail portion includes an eyelet 60 through which a cord 62 extends for attachment to an eyelet 64 on the rearward end of the boom 48.

Because of the efficiency of a sail decreases with increasing flexibility, it is desirable to minimize flexing of the flexible sail portion 28. To this end, the same is heavily battened with a plurality of battens 66.

The airfoil 26 is shown in a partially assembled form in FIG. 2 and includes a leading edge tube 68 spaced forwardly of the sheath 44 and which defines the forward edge of the airfoil 26. Extending between the tube 68 and the sheath 44, on both sides thereof, are skinlike sheets 70 which define the surface of the airfoil. According to one embodiment, the sheets 70 may be formed of aeronautical aluminum wind skin having a thickness of approximately fifteen thousandths of an inch. As seen in FIG. 3, the skin-like sheets 70 are bowed to define the airfoil and tangentially intersect corresponding sides of the leading edge tube 68 and the sheath 44 to hold the sheets 70 in assembled condition with the tube 68 and the sheath 44. Each of the latter, on both sides thereof, is provided with elongated moldings 72. The moldings 72 may be formed of any desired material and are secured to tube 68 and the sheath 44 in any suitable manner. Of principal importance is the fact that the trailing edges of the same in the case of the tube 68 or the leading edges of the same in the case of the sheath 44, include tabs 72 spaced outwardly from the surface of the tube 68 or the sheath 44 to provide an entry space for the sheets 70 as illustrated in FIG. 4.

The inherent resilience of the sheets 70 when bowed as indicated in FIG. 3 serves to exert a separating force between the leading tube 68 and the sheath 44. To oppose the force and to limit separation, three turnbuckles 74 extend between the sheath 44 and the tube 68 at the approximate locations illustrated in FIG. 2. The ends of the turnbuckles 74 are received in keyhole slots 76 and adjustment of the same may be employed to adjust the camber of the airfoil 26 for maximum efficiency. In particular, the lower turnbuckle 74 may be adjusted through an open space at the underside of the airfoil 26 while the central turnbuckle 74 may be adjusted by opening an access door 78 provided in one of the skins 70 adjacent the central turnbuckle 74. The upper turnbuckle 74 may be adjusted through an opening 80 in an end plate 82 for thesail 24. The end plate 82 is also provided with an elongated slot 84 through which a bolt 86 extends to be secured to the leading edge tube 68. The slot 84 accommodates the adjustable movement of the leading edge tube 68 relative to the sheath 44.

As a result of the foregoing construction, an easily disassembled airfoil 26 is provided to overcome objections to the prior use of such airfoils in sailing crafts. Specifically, it is only necessary to loosen the turnbuckles 74 sufficiently to remove the skins 70 which may then be coiled in rolls for storage.

FIG. 2 also illustrates airfoil angle control structure. Specifically, there is provided a semicircular tube 88 having inwardly directed ends 90 which is secured to the sheath 44 near its lower end. The radius of the semicircular tube 88 is chosen to be constant and at one or more points radially spaced from the mast 22 a distance equal to the radius of the semicircular tube 88 guides 92 having lips 94 overlapping the upper side of the tube 88 are provided. One or more of the guides 92 may pivotally and eccentrically mount key-shaped elements 86 having a handle 98 at one end. The arrangement is such that when the handle 98 is moved upwardly about the pivot point of the key-shaped member 96, and increasing clamping pressure is applied against the tube 88 to hold the same in a desired rotative position, thus holding the airfoil 26 in a desired angular relation with regard to the main hull 10. When it is desired to change the position of the airfoil 26, the handle 98 may be moved downwardly to release the clamping pressure whereupon the position may be adjusted.

The semicircular tube 80 also mounts two outwardly extending eyes 100 (only one of which is shown). The two eyes 100 are located symmetrically on the tube 88 and are spaced a distance of about 90 from one another. Each serves to secure one end of a respective block and tackle 102 which serve as sheet means for controlling the angular position of the flexible sail portion 28 relative to the airfoil 26. The other end of each block tackle is secured to a' depending eye 104 on the boom 48. The free ends of cords-106 associated with each block and tackle 102 are led to the cockpit 20 where they may be manipulated by the operator of the craft as sail sheets.

Turning now to FIG. 5, the steering and lift control mechanism 34 will be described. As mentioned previously, the same includes an inverted, 'V-shaped hydrofoil 38. As illustrated in FIG. 5, th e same includes a rearwardly directed tail including a slot 110. In addition, at the apex of the V of the hydrofoil 38, there is provided a groove 112 for receipt of one end of a shaft 114 journaled in the stern on the main hull by bearings 116 for rotation about a vertical axis. A pivot pin 118 connects the hydrofoil 30 to the lower end of the shaft 114. v

The upper end of the shaft 114 terminatesin a yoke 120 which receives an elongated tiller 122 intermediate its ends and pivotally mounts the same for rotation about a horizontal axis by means of a pivot pin 124. One end of the tiller 122 mounts the handle 36 which may be grasped by an operator within the cockpit so that the tiller 122 may be moved'upwardly or downwardly or to the right or to the left. The other end of the tiller 122 mounts a yoke 126 which is pivotally connected by means of a pivot pin 128 to a link 129 extending downwardly into the slot 110 in the hydrofoil 38 and pivotally connected thereto by means not shown.

As a result of the foregoing construction, it will be appreciated that movement of the tiller 122 to the right will result in corresponding pivoting of the hydrofoil 38 to cause the craft to turn to the leftas would be the case for the same type of manipulation for a conventional tiller. By the same token, upward or downward movement of the grip 124 will cause pivoting of the hydrofoil 38 about the axis of pivot pin 118 to alter the angle of attack on the hydrofoil 38 and thus vary the lift characteristics of the same to control the lift of the overall craft.

Turning now to FIG. 6, a means by which the hydrofoil elements 40 may be adjustably secured to their associated outrigger hulls will be described. In particular, the hydrofoil element 40 is secured to a mounting plate 130 which in turn is connected to the associated outrigger hull by a hinge 132 having ahinge pin 133. Spaced downwardly from the axis of the hinge 132 and projecting away from the hydrofoil element 40 and secured to the plate is a multi-apertured element 134. Mounted for reciprocation within the outrigger hull 12 is an elongated rod 136 which is arranged to be received in one of the apertures of the multi-apertured element 134. As illustrated, two apertures are provided and the rod 136 is received in one of the apertures and is oriented such that the angle of the hydrofoil 40 with respect to the horizontal plane would be about 30. For lesser loads, it would be desirable to increase that angle to perhaps as much as 60 and to this end, it is only necessary to pull upwardly on an eyelet 138 at the upper end of the rod 136 to remove the same from the apertures in the element 134 in which it is shown to be located. At this point, the hydrofoil 40 may be pivoted downwardly about the hinge 132 and the rod 136 caused to enter the other aperture in the element 134 which is positioned to provide about a 60 angle. Of course, additional apertures may be provided for intermediate points of adjustment, if desired.

For storage or transportation purposes, the hydrofoils 40 may be removed from their respective outrigger hulls simply by disengaging the rod 136 from the aperture in which it may be lodged and by removing the hinge pin 133 from the hinge 132. This will result in disconnection of the mounting plate 130 from the respective outrigger hull whereupon the hydrofoils 40 may be stored.

The construction described in the preceding paragraph also permits use of the vessel for purposes other than sailing over water. For example, with suitable attachments to be employed in lieu of the hydrofoils 38 and 40, the vessel may be used for ice boating and with reference to FIGS. 7 and 8, appropriate attachments will be described. FIG. 7 illustrates a runner 140 which may be employed in lieu of the hydrofoil 38. On the upper side of the runner 140 and midway along its length there is provided an upwardly open channel bracket 142 having aligned horizontal apertures 144. The rear end of the runner 140 includes a rearwardly extending attachment bracket 146. By disconnecting the pivotal connections of the hydrofoil 38 to the shaft 114 and the link 129, and connecting the' bracket 142 to the shaft 114 and the bracket 146 to the link 129, a rudder runner for ice boating is provided. Of course, for ice boating, the link .129 will be ineffectual as there is no need to pivot the runner 140 about a horizontal axis.

FIG. 8 illustrates an outrigger runner for attachment to the outrigger hull 12. A runner formed as a mirror image of that illustrated in FIG. 8 may be employed in conjunction with the outrigger hull 14.

The outrigger runner illustrated in FIG. 8 includes a runner body 148 secured to a mounting plate 150 generally similar to the mounting plate 130. Secured to the mounting plate 150 is an apertured bracket 151 which serves the same function in conjunction with the rod 136 as the multi-apertured bracket 134 except that the bracket 151 is arranged so that when the rod 136 is received in the aperture thereof, the runner 148 will be arranged in substantially a vertical plane.

The upper side of the mounting plate 150 terminates in a half hinge portion 152 which meshes with that portion of the hinge 132 on the outrigger hull and by replacing the hinge pin 133 in the same while locating the rod 136 in the bracket 150, the vessel may be converted to an ice boat.

From the foregoing, it will be appreciated that a sailing craft made according to the invention provides a significant increase in the efficiency over conventional sailing craft by reason of its use of an airfoil as a sail and the employment of hydrofoils and without the drawbacks normally associated with the use of either of such features. For example, the use of the outrigger hulls mounting the hydrofoils provides a substantial increase in stability of the craft during operation. In particular, if during operation the wind is such as to cause the boat to heel to one side, the windward hydrofoil 40 will tend to be lifted out of the water thereby decreasing the lift on the windward side of the craft while the leeward hydrofoil 40 will be forced deeper into the water. In addition, the pivoting action of the craft during heeling will cause the leeward foil to become more horizontal, and as a result, the resultant increase in lift due to the change of angle of the leeward hydrofoil as well as the increased submergence of the same tends to immediately right the craft so that there is no danger of capsizing.

The unique combination steering and lift control is also of substantial assistance in efficient operation. For example, moving the grip downwardly tends to increase the effective angle of attack of the foils 40 on the outrigger hulls. By the same token, moving the handle upwardly effectively decreases the angle of attack. As a result, overall lift can be effectively controlled through a relatively simple mechanism.

Significantly, all of the foregoing advantages are achieved in a sailing craft made according to the invention without sacrificing ease of storage or transportation thus providing a hydrofoil sailing craft having substantial appeal to the ordinary boating enthusiast. And the convertibility aspect whereby the vessel may also be employed for ice boating increases the appeal by providing flexibility of purpose enabling year around use. Similarly, by simply removing the hydrofoils 40 in the manner mentioned previously, the craft may be used for conventional sailing.

I claim:

1. A hydrofoil sailing craft comprising: a buoyant elongated main hull; a mast extending upwardly from said main hull; means defining a sail on said mast; a pair of buoyant outrigger hulls each of substantially lesser length than said main hull, one on each side of said main hull and spaced therefrom and each secured thereto, each of said outrigger hulls having at least a portion extending substantially forwardly of said main hull; at least two hydrofoil elements, one on each outrigger hull and extending downwardly toward the other outrigger hull; a steering device comprising a V-shaped hydrofoil pivotally secured to said main hull for rotation relative thereto about a substantially vertical axis; said sail comprising an airfoil extending forwardly of said mast and a trailing sail portion extending rearwardly of said mast and being pivotally secured thereto; means mounting one of said mast and said airfoil for pivotal movement relative to said main hull; means for securing said airfoil in a desired position of rotation relative to said main hull; and means for controlling the position of said sail portion relative to said airfoil.

2. The hydrofoil sailing craft of claim 1 wherein said airfoil is secured to said mast and said mast is pivotally mounted on said main hull; and said securing means comprises a semi-circular element secured to said airfoil to be movable therewith and at least one locking device on said main hull operatively associated with said semi-circular element for locking the latter against rotation relative to said main hull; and said means for controlling the position of said sail portion comprise means for movably interconnecting said sail portion and said semi-circular element.

3. A hydrofoil sailing craft comprising: a buoyant elongated main hull; a mast extending upwardly from said main hull; means defining a sail on said mast; a pair of buoyant outrigger hulls each of substantially lesser length than said main hull, one on each side of said main hull and spaced therefrom and each secured thereto, each of said outrigger hulls having at least a portion extending substantially forwardly of said main hull; at least tow hydrofoil elements, one on each outrigger hull forwardly of said main hull and extending downwardly toward the other outrigger hull; and a steering device comprising a V-shaped hydrofoil pivotally secured to said main hull for rotation relative thereto about a substantially vertical axis.

4. The hydrofoil sailing craft of claim 3 wherein said V-shaped hydrofoil is pivotally secured to said hull for rotation about said vertical axis by a substantially vertical, rotatable shaft and said V-shaped hydrofoil is pivotally mounted for movement about a horizontal axis by a pivot at one end of said shaft; and a common actuator comprising an elongated handle; said handle being secured intermediate its ends to the other end of said shaft by means of a pivotal connection having a generally horizontal axis; and a link extending from one end of said handle to said V-shaped hydrofoil and pivotally interconnecting the same.

5. A sailing craft according to claim 3 wherein the outrigger hulls are respectively secured to the main hull by at least one structural member, each structural member comprising at least two elements releasably secured together.

6. A sailing craft according to claim 3 further including a set of additional craft support elements interchangeable with said hydrofoil elements and said V- shaped hydrofoil, said additional craft support elements comprising iceboat runners.

7. The hydrofoil sailing craft of claim 3 further including means for adjustably securing each of said hydrofoil elements at a desired downwardly extending angle relative to their respective outrigger hulls.

8. A hydrofoil sailing craft according to claim 7 wherein each of said hydrofoils is pivotally connected to its respective outrigger hull by means of hinge means; and said adjustable means comprise a multipleapertured element on each of said hydrofoils, and a movable locking pin on a respective one of said outrigger hulls and adapted to be selectively received in any one of the apertures of the respective apertured member to lock the hydrofoil in a corresponding position of rotation relative to its respective hinge means.

9. The hydrofoil sailing craft of claim 3 wherein said sail comprises a relatively rigid airfoil secured to said mast, and means establishing a pivotal connection between said main hull and one of said mast and said airfoil.

10. The hydrofoil sailing craft according to claim 9 wherein said airfoil is defined by a first, upright rigid member spaced forwardly of said mast and a second, upright rigid member associated with said mast, a pair of semi-rigid skin-like sheets extending between said rigid members, one on each side thereof, and means for adjusting the distance between said rigid members whereby the camber of the airfoil may be adjusted. 

1. A hydrofoil sailing craft comprising: a buoyant elongated main hull; a mast extending upwardly from said main hull; means defining a sail on said mast; a pair of buoyant outrigger hulls each of substantially lesser length than said main hull, one on each side of said main hull and spaced therefrom and each secured thereto, each of said outrigger hulls having at least a portion extending substantially forwardly of said main hull; at least two hydrofoil elements, one on each outrigger hull and extending downwardly toward the other outrigger hull; a steering device comprising a V-shaped hydrofoil pivotally secured to said main hull for rotation relative thereto about a substantially vertical axis; said sail comprising an airfoil extending forwardly of said mast and a trailing sail portion extending rearwardly of said mast and being pivotally secured thereto; means mounting one of said mast and said airfoil for pivotal movement relative to said main hull; means for securing said airfoil in a desired position of rotation relative to said main hull; and means for controlling the position of said sail portion relative to said airfoil.
 2. The hydrofoil sailing craft of claim 1 wherein said airfoil is secured to said mast and said mast is pivotally mounted on said main hull; and said securing means comprises a semi-circular element secured to said airfoil to be movable therewith and at least one locking device on said main hull operatively associated with said semi-circular element for locking the latter against rotation relative to said main hull; and said means for controlling the position of said sail portion comprise means for movably interconnecting said sail portion and said semi-circular element.
 3. A hydrofoil sailing craft comprising: a buoyant elongated main hull; a mast extending upwardly from said main hull; means defining a sail on said mast; a pair of buoyant outrigger hulls each of substantially lesser length than said main hull, one on each side of said main hull and spaced therefrom and each secured thereto, each of said outrigger hulls having at least a portion extending substantially forwardly of said main hull; at least tow hydrofoil elements, one on each outrigger hull forwardly of said main hull and extending downwardly toward the other outrigger hull; and a steering device comprising a V-shaped hydrofoil pivotally secured to said main hull for rotation relative thereto about a substantially vertical axis.
 4. The hydrofoil sailing craft of claim 3 wherein said V-shaped hydrofoil is pivotally secured to said hull for rotation about said vertical axis by a substantially vertical, rotatable shaft and said V-shaped hydrofoil is pivotally mounted for movement about a horizontal axis by a pivot at one end of said shaft; and a common actuator comprising an elongated handle; said handle being secured intermediate its ends to the other end of said shaft by means of a pivotal connection having a generally horizontal axis; and a link extending from one end of said handle to said V-shaped hydrofoil and pivotally interconnecting the same.
 5. A sailing craft according to claim 3 wherein the outrigger hulls are respectively secured to the main hull by at least one structural member, each structural member comprising at least two elements releasably secured together.
 6. A sailing craft according to claim 3 further including a set of additional craft support elements inter-changeable with said hydrofoil elements and said V-shaped hydrofoil, said additional craft support elements comprising iceboat runners.
 7. The hydrofoil sailing craft of claim 3 further including means for adjustably securing each of said hydrofoil elements at a desired downwardly extending angle relative to their respective outrigger hulls.
 8. A hydrofoil sailing craft according to claim 7 wherein each of said hydrofoils is pivotally connected to its respective outrigger hull by means of hinge means; and said adjustable means comprise a multiple-apertured element on each of said hydrofoils, and a movable locking pin on a respective one of said outrigger hulls and adapted to be selectively received in any one of the apertures of the respective apertured member to lock the hydrofoil in a corresponding position of rotation relative to its respective hinge means.
 9. The hydrofoil sailing craft of claim 3 wherein said sail comprises a relatively rigid airfoil secured to said mast, and means establishing a pivotal connection between said main hull and one of said mast and said airfoil.
 10. The hydrofoil sailing craft according to claim 9 wherein said airfoil is defined by a first, upright rigid member spaced forwardly of said mast and a second, upright rigid member associated with said mast, a pair of semi-rigid skin-like sheets extending between said rigid members, one on each side thereof, and means for adjusting the distance between said rigid members whereby the camber of the airfoil may be adjusted. 